Python KivyMD: How can I make the toggle_nav_drawer() function work?

Question

I got a problem with my kv code here. I want to create a MDNavigationDrawer with a few NavigationDrawerIconButtons. The window shows up but when I clic

Answer 1

Error - AttributeError

     left_action_items: [['dots-vertical', lambda x: root.toggle_nav_drawer()]]
   File "kivy\weakproxy.pyx", line 32, in kivy.weakproxy.WeakProxy.__getattr__
 AttributeError: 'LayoutPy' object has no attribute 'toggle_nav_drawer'

Root Cause

The object, LayoutPy does not has an attribute toggle_nav_drawer because the toggle_nav_drawer is defined in the instantiated child, NavigationLayout: of LayoutPy.

Solution

Replace root.toggle_nav_drawer() with root.ids.nav_layout.toggle_nav_drawer()

Snippets - kv file

BoxLayout:
    orientation: 'vertical'

    MDToolbar:
        id: toolbar
        title: 'Menu'
        md_bg_color: app.theme_cls.primary_color
        background_palette: 'Primary'
        background_hue: '500'
        left_action_items: [['dots-vertical', lambda x: root.ids.nav_layout.toggle_nav_drawer()]]

Output